关于enq: TX – row lock contention的测试和案例分析
1、主键或唯一index
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---session 1 SQL> select sid from v$mystat where rownum=1; SID ---------- 130 SQL> create table t1_tx(id number primary key,name varchar2(20)); Table created. SQL> insert into t1_tx values(1,'roger'); 1 row created. SQL> commit; Commit complete. SQL> insert into t1_tx values(2,'xxoo'); 1 row created. ---session 2 SQL> conn roger/roger Connected. SQL> select sid from v$mystat where rownum=1; SID ---------- 69 SQL> insert into t1_tx values(2,'xxoo'); ---一直处于等待状态 ---session 3 SQL> select sid, 2 chr(bitand(p1, -16777216) / 16777215) || 3 chr(bitand(p1, 16711680) / 65535) "Name", 4 (bitand(p1, 65535)) "Mode",event,sql_id,FINAL_BLOCKING_SESSION 5 from v$session 6 where event like 'enq%'; SID Name Mode EVENT SQL_ID FINAL_BLOCKING_SESSION ---------- ---- ----- ------------------------------ ------------- ---------------------- 69 TX 4 enq: TX - row lock contention b775wqk86zc6k 130 SQL> select sid,serial#,username,sql_id from v$session where sid=130; SID SERIAL# USERNAME SQL_ID ---------- ---------- ------------------------------ ------------- 130 185 ROGER SQL> select * from v$Lock where block=1; ADDR KADDR SID TY ID1 ID2 LMODE REQUEST CTIME BLOCK -------- -------- ---------- -- ---------- ---------- ---------- ---------- ---------- ---------- 2A4F2AAC 2A4F2AEC 130 TX 196612 895 6 0 736 1 |
可以看出,对于表存 […]